Visible light communication (VLC) involves modulating information to be carried by a visible light used as a carrier. More specifically, visible light that is used to illuminate a location can be modulated with information so that electronic equipment under the coverage of visible light may receive information from the visible light that is modulated with information. A light-emitting diode (LED) can be used to provide the visible light. Since the original purpose of light is to illuminate a location, and visible lights are pervasive, using visible light to communicate may not significantly require alternations of existing infrastructures. VLC has the advantages of having secure communication channels, being relatively immune to interference relative to other forms of communications and also is currently not known to cause electromagnetic injuries.
Multi-band orthogonal frequency-division multiplexing (OFDM) used in modulating different light-emitting diodes (LEDs) in VLC may reduce non-linear distortions and may increase transmission rates. However, conventional VLC techniques achieve an increase of transmission rates only in the overlapping regions of the light sources, while other regions achieve low transmission rate. Moreover, conventional schemes that perform optimization of the LED driving circuit and the receiving end circuit have limited effects due to the limited response and output power of the LED light sources. Other schemes attempt to add blue filters in the receiving end, but these techniques may drastically increase the cost of the receiving modules by adding optical filters. Wavelength division multiplexing (WDM) transmission techniques, on the other hand, require costly RGB light sources and wavelength selection filters in the receiving end.
Therefore, the disclosure provides a VLC apparatus and a method of VLC that would improve upon conventional schemes.